Method of making an electric blanket



Oct. 26, 1965 L. c. owl-:Rs 3,213,521

METHOD OF MAKING AN ELECTRIC BLANKET Original Filed June 15, 1961 16 1417 FIGA.

'lhvenJr-ov l.. C. @weas #mais United States Patent O 3,213,521 METHOD FMAKING AN ELECTRIC BLANKET Leonard C. Owers, Colbury, near Totton,England, as-

signor to Frederick Williams (Appliances) Limited, Southampton, England,a British company Original application .lune 15, 1961, Ser. No. 117,388,now Patent No. 3,102,186, dated Aug. 27, 1963. Divided and thisapplication Aug. 23, 1962, Ser. No. 219,069 Claims priority, applicationGreat Britain, July 8, 1960,

23,935/ 60 4 Claims. (Cl. 29-155.63)

This invention relates to electric blankets and more particularly to amethod of making such blankets.

In my co-pending patent application Serial No. 117,388, filed June 15,1961 and now Patent No. 3,102,186, issued August 27, 1963 of which thepresent application is a division, I have described and claimed anelectrically heated blanket comprising two inner layers of syntheticplastics material, a heating element consisting of conductor wires laidin reversing lines spaced in substantially parallel relationship, andinterposed between said two layers of material and two outer layers offabric covering respectively the outer surfaces of said inner layers,said inner layers being bonded together and to the fibres of the outerfabric covering layers by welding along lines disposed between the linesof the conducting wire.

The object of the present invention is to provide a method which permitsthe rapid assembly of the various layers of the blanket and thesubsequent completion of the manufacture.

The method according to the invention is illustrated in the accompanyingdrawings, in which FIG. 1 is a plan view of a finished blanket made inaccordance with the invention.

FIG. 2 is `an enlarged cross section taken on the line II-II, FIG. 1.

FIG. 3 illustrates a jig on which the various layers of the blanket maybe assembled during the course of manufacture, and FIG. 4 illustratesthe assembly of the various layers of the blanket prior to the weldingoperation.

Referring first to FIG. 3 this gure shows a jig comprising a rectangularaluminum plate having -a thickness of approximately W16 and havingadjacent each end a plurality of steel pointed pins 11, 12.

The various layers of the blanket and the heating element are assembledon this jig in the following sequence. An outer or covering layer 13 offabric is first placed on the jig with the pins 11, 12 passing throughthe layer, and a layer 14 of polyvinyl chloride wadding or foam is thensimilarly placed on the covering material 13 with the pins 11, 12-passing through this layer 14. A canvas square 15 holding the mainslead 16 is placed in position and conducting wire 17 is then woundaround the pins 11, 12 to form the heating element which is connected tothe mains lead 16. A second layer 18 of polyvinyl chloride wadding orfoam and a second outer or covering layer 19 of fabric are thensuccessively placed on the exposed side of the heating element 17, thewhole assembly being held in place on the aluminum plate by the pins 11,12. When the assembly has thus been completed the various layers of theassembly are welded or fused together by means of a high frequencyelectronic or other suitable welding machine, along a plurality ofquilting lines 21.

This welding operation produces fusion of the two thermoplastic layersalong the weld lines and causes the layers to be Ibonded together and tothe bres of the outer covering layers whereby all the layers of theassembly are joined together -along the weld lines.

The quilting lines 21 are disposed between the runs of the wire 17 insuch a way that the wire 17 is positively positioned.

ICC

A satin binding tape may be sewn around the edges of the assembly, ifrequired.

The fabric covering material 13, 19 in the above embodiment may becot-ton, cotton/rayon mixture or wool mixture.

As will be apparent from the foregoing description the method accordingto the invention permits of rapidly assembling the various layers of theblanket with the heating element laid and correctly positioned betweenthe inner layers, the manufacture being thereafter completed by a simplewelding operation.

What I claim and desire to secure by Letters Patent is:

1. The method of assembling the layers of an electric blanket on a jigcomprising a plate having adjacent each end a series of spaced pins,consisting in successively assembling on said jig a first outer layer offabric and a rst inner layer of -synthetic heat weldable thermoplasticfoam, with said pins passing through said layers, winding in reversinglines around and between said pins an electrically conducting wire toform spaced parallel heating elements extending lengthwise across saidrst inner layer, successively assembling on said jig a second innerlayer of synthetic heat weldable thermoplastic foam and a second outerlayer of fabric with said pins passing through said layers, andconnecting said inner layers together and to said outer layers alongspaced lines between said heating elements by weld lines which serve tomaintain said heating elements in correct spaced relationship, the saidouter layers being joined together and to the said inner layers alongsaid weld lines by fusion of the said inner layers produced when welded.

2. The method of assembling the layers of an electric blanket on a jigcomprising a plate having adjacent each end a series of spaced pinsyconsisting in successively assembling on said jig a first outer layer offabric and a rst inner layer of synthetic heat weldable thermoplasticwadding with said pins passing through said layers, winding in reversinglines around and between said pins an electrically conducting wire toform spaced parallel heating elements extending lengthwise across saidfirst inner layer, successively assembling on said jig a second innerlayer of synthetic heat weldable thermoplastic wadding and a secondouter layer of fabric with said pins passing through said layers, andconnecting said inner layers together and to said outer layers alongspaced lines between said heating elements `by weld lines which serve tomaintain said heating elements in correct spaced relationship, the saidouter layers being joined together and to the said inner layers alongsaid weld lines by fusion of the said inner layers produced whenwelding.

3. The method of assembling the layers of an electric blanket on a jigcomprising a plate having adjacent each end a series of spaced pinsconsisting in successively lassembling on said jig a first outer layerof fabric and an inner layer of synthetic heat weldable thermoplasticfoam, with said pins passing through said layers, winding in reversinglines around and between said pins an electrically conducting wire toform spaced parallel heating elements extending lengthwise across saidfoam inner layer, successively assembling on said jig an inner layer ofsynthetic heat weldable thermoplastic wadding and a second outer layerof fabric with said pins passing through said layers, and connectingsaid inner layers together and to said outer layers along spaced linesbetween said heating elements by weld lines which serve to maintain saidheating elements in correct spaced relationship, the said outer layersbeing joined together and to the said inner layers along said weld linesby fusion of the said inner layers produced when welding.

4. The method of assembling the layers of an electric blanket on a jigcomprising a plate having adjacent each end a series of spaced pinsconsisting in successively assembling on said jig a first outer layer offabric and an inner layerof synthetic heat Weldable thermoplasticwadding with said pins passing through said layers, winding in reversinglines around and between said pins an electrically conducting wire toform spaced parallel heating elements extending lengthwise across saidwadding inner layer, successively assembling on said jig an inner layerof synthetic heat weldable thermoplastic foam and a second layer offabric with said pins passing through said layers, and connecting saidinner layers together and t0 said outer layers `along spaced linesbetween said heating elements by weld lines which serve to maintain saidheating elements in correct spaced relationship, the said outer layersbeing joined together and to the said `inner layers References Citedrbythe Examiner UNITED STATES PATENTS Steinberger 219-46 Crise 219-46 DeMichele 29155.68 Suchy 219-46 Kerr 219-46 De Michele 29-155.62 King.Z9-155.68

WHITMORE A. WILTZ, Primary Examiner.

along said weld lines by fusion of the said inner layers 15 JOHN F.CAMPBELL, Examiner.

produced when Welding.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,213,521 October 26, 1965 Leonard C Owers It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

In the grant, lines 2 and 3, for "assignor to Frederick Williams(Appliances) Limited, of Southampton, England, a British company" readassignor to Dreamland Electrical Appliances Limited, of Southampton,England, a British company line l2, for "Frederick Williams (Appliances)Limited, its successors" read Dreamland Electrical Appliances Limited,its successors in the heading to the printed specification, lines 3 toS, for "assignor to Frederick Williams (Appliances) Limited,Southampton, England, a British company" read assignor to DreamlandElectrical Appliances Limited, Southampton, England, a British companySigned and sealed this llth day of October 1966.,

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. THE METHOD OF ASSEMBLING THE LAYERS OF AN ELECTRIC BLANKET ON A JIGCOMPRISING A PLATE HAVING ADJACENT EACH END A SERIES OF SPACED PINS,CONSISTING IN SUCESSIVELY ASSEMBLING ON SAID JIG A FIRST OUTER LAYER OFFABRIC AND A FIRST INNER LAYER OF SYNTHETIC HEAT WELDABLE THERMOPLASTICFOAM, WITH SAID PINS PASSING THROUGH SAID LAYERS, WINDING IN REVERSINGLINES AROUND AND BETWEEN SAID PINS AN ELECTRICALLY CONDUCTING WIRE TOFORM SPACED PARALLEL HEATING ELEMENTS EXTENDING LENGTHWISE ACROSS SAIDFIRST INNER LAYER, SUCCESSIVELY ASSEMBLING ON SAID JIG A SECOND INNERLAYER OF SYNTHETIC HEAT WELDABLE THERMOPLASTIC FOAM AND A SECOND OUTERLAYER OF FABRIC WITH SAID PINS PASSING THROUGH SAID LAYERS, ANDCONNECTING SAID INNER LAYERS TOGETHER AND TO SAID OUTER LAYERS ALONGSPACED LINES BETWEEN SAID HEATING ELEMENTS BY WELD LINES WHICH SERVE TOMAINTAIN SAID HEATING ELEMENTS IN CORRECT SPACED RELATIONSHIP, THE SAIDOUTER LAYERS BEING JOINED TOGETHER AND TO THE SAID INNER LAYERS ALONGSAID WEL D LINES BY FUSION OF THE SAID INNER LAYERS PRODUCED WHENWELDED.